A driving assistance system proposed in the related art detects a three-dimensional object existing in front of a host vehicle, and after predicting contact between the detected three-dimensional object and the host vehicle, issues a warning to a driver and performs an automatic driving operation to avoid contact between the host vehicle and the three-dimensional object.
In a conventional technique employed in a driving assistance system such as that described above, a three-dimensional object existing on the periphery of the host vehicle is detected using a camera, a laser radar, or the like, and steering or braking operation assistance is implemented on the basis of a degree of risk, which is determined in accordance with the type of the three-dimensional object and a time leeway (TTC: Time To Collision) (see Patent Document 1, for example).